Neoplastic transformation of intra- and extra-hepatic biliary epithelial cells (cholangiocytes), gives rise to cholangiocarcinoma, a devastating cancer that has a very poor prognosis. Early diagnosis is difficult as symptoms usually arise as a result of bile duct blockage and relative resistance to current chemotherapies makes for a short life expectancy after diagnosis. Therefore, research into the control of cholangiocarcinoma cell growth is imperative to design more effective treatment strategies. We have obtained novel preliminary data indicating that there is an over production of the growth factor progranulin in cholangiocarcinoma cells and tissue and thus, suggest that this factor may play a role in the progression of cholangiocarcinoma. The overall objective of this proposal is to determine the molecular mechanisms by which progranulin is upregulated and to determine the consequences of increased progranulin production on cell growth. Our proposed work will focus on two specific aims that have been designed to test the following hypotheses: 1) Progranulin is upregulated in cholangiocarcinoma as a result of aberrant IL-6 expression via an ERK1/2/RSK/C/EBP(-dependent pathway. 2) Progranulin has growth promoting properties on cholangiocarcinoma via the IP3/Ca2?dependent inhibition of FOXO1 transcriptional activity. The elucidation of the mechanism by which progranulin production is increased in cholangiocarcinoma and the consequences of the increased progranulin levels on cholangiocarcinoma cell growth will be important in understanding the etiology of cholangiocarcinoma and may play a paramount role in the development of therapeutic strategies for the treatment of cholangiocarcinoma. PUBLIC HEALTH RELEVANCE: Cholangiocarcinoma is a devastating cancer of the biliary tract that has poor prognosis and limited treatment options. The health relatedness of this application is that dissecting the mechanisms that may be responsible for the malignant transformation of cholangiocytes (cells that line the biliary tree) into cholangiocarcinoma can ultimately be expected to provide understanding of the causes of cholangiocarcinoma and increase opportunities for the development of novel treatment regimes for the treatment of this deadly cancer.